<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }
    #container {
      height: 100vh;
      display: flex;
      flex-direction: column;
    }
    .header {
      height: 60px;
      background-color: #4cae4c;
    }
    .main {
      flex: 1;
      background-color: #ccc;
    }
    .footer {
      display: flex;
      height: 50px;
      background-color: #8c8c8c;
      justify-content: space-between;
      border-top: 2px solid rebeccapurple;
    }
    .footer section {
      flex: 1;
      display: flex;
      border-right: 2px solid rebeccapurple;
      flex-direction: column-reverse;
    }
    .footer section H4 {
      display: flex;
      flex: 0 0 50px;
      justify-content: center;
      align-items: center;
      cursor: pointer;
    }
    .footer section ul {
      display: flex;
      flex-direction: column;
      border: 1px solid rosybrown;
    }
    .footer section ul li {
      display: flex;
      justify-content: center;
      align-items: center;
      flex: 1 0 50px;
      list-style: none;
      border-bottom: 2px silver solid;
      cursor: pointer;
    }
    .footer section:last-child {
      border-right: none;
    }

  </style>
</head>
<body>
  <div id="container">
    <div class="header"></div>
    <div class="main"></div>
    <div class="footer">
      <section>
        <h4>教程</h4>
        <ul>
          <li>教程</li>
          <li>活动</li>
          <li>论坛</li>
          <li>关于</li>
        </ul>
      </section>
      <section>
        <h4>教程</h4>
        <ul>
          <li>教程</li>
          <li>活动</li>
          <li>论坛</li>
          <li>关于</li>
        </ul>
      </section>
      <section>
        <h4>教程</h4>
        <ul>
          <li>教程</li>
          <li>活动</li>
          <li>论坛</li>
          <li>关于</li>
        </ul>
      </section>
      <section>
        <h4>教程</h4>
        <ul>
          <li>教程</li>
          <li>活动</li>
          <li>论坛</li>
          <li>关于</li>
        </ul>
      </section>
      <section>
        <h4>教程</h4>
        <ul>
          <li>教程</li>
          <li>活动</li>
          <li>论坛</li>
          <li>关于</li>
        </ul>
      </section>
    </div>
  </div>
</body>
</html>
